Natural and anthropogenic enrichments of As,Cu, Pb,Sb, and Zn in ombrotrophic versus minerotrophic peat bog profiles,Jura Mountains,Switzerland

Peat cores were taken from two contrasting Sphagnum bogs in the Jura Mountains of Switzerland. At Etang de la Gruyere (EGr), 6.5 m of peat has accumulated during the past 10,000 years. In the first 100 cm of this profile there are several distinct peaks in ash content, but the values are well within the range for typical ombrotrophic Sphagnum bogs. There is also considerable variation in the concentrations of major and trace lithogenic metals (Al, Ti, Sc, Ca, Mg, Rb, and Sr), but most of this is simply a reflection of the natural variations in the amount of mineral matter in the peats. The Ca/Mg molar ratios in the peats at EGr are comparable to or lower than the average rainwater composition in this area, showing that this section of the peat core is ombrotrophic (i.e. rainwater-fed). In other words, the inorganic constituents in the surface peats at EGr were supplied exclusively by atmospheric deposition. This peat core, therefore, is suitable for studying the historical record of atmospheric metal deposition. Arsenic, Cu, Pb, Sb, and Zn are all more abundant in surface and near surface peat layers compared to deeper parts of the profile. Enrichment factors (EFs) for the profile were calculated conservatively by normalizing the metal/Sc ratios of individual peat samples to the average of the five lowest metal/Sc ratios in this part of the core (69–84 cm); these are tentatively assumed to represent pre-Industrial background values. The maximum EFs are approximately 5 times for Cu, 15 times for As, and 30 to 50 times for Pb, Sb, and Zn. At La Tourbière des Genevez (TGe), 1.5 m of peat represents 4,800 years of peat formation. At this site, the ash contents are higher and increase progressively with depth to values which are characteristic of minerotrophic fen peats. The concentration profiles of Al, Ti, Sc, Ca, Mg, Rb, Sr show the same general trend. The Ca/Mg molar ratios of these peats are generally twice the rainwater average, showing that this bog is essentially minerotrophic (ie groundwater-fed). Thus, the inorganic cccstituents in these peats were provided by both atmospheric and hydrospheric processes. Despite this, the Cu, Pb, Sb, and Zn concentrations are generally very similar to those at EGr, especially in the uppermost part of the profile, indicating that recent atmospheric inputs also dominate the supply of these metals to this bog. However, the minimum Pb and Sb concentrations in this profile are approximately five times higher than the corresponding values at EGr. The minerotrophic profile at TGT, therefore, could not by itself be used to calculate rates of atmospheric Pb and Sb deposition because it is impossible to distinguish between atmospheric and hydrospheric metal inputs. At TGe, As concentrations increase continuously with depth, reaching concentrations in the deeper, older peats which are more than 50 times higher than the ‘background’ As values at EGr. At this site the natural supply of As by mineral soil water completely masks the recent, elevated inputs contributed by atmospheric deposition. Thus, the peat core from TGe is also unsuitable for studying atmospheric As deposition.     

Humic-rich peat extracts inhibit sulfate reduction, methanogenesis, and anaerobic respiration but not acetogenesis in peat soils of a temperate bog

To understand why anaerobic ombrotrophic peats can be very low in methane after drainage related afforestation, we analyzed the competition of sulfate reducing, humus reducing, and methanogenic microorganisms by incubating ombrotrophic peats of the Mer Bleue bog, Ontario. Sulfate, sulfide, and sulfate containing peat dissolved organic matter (DOM) from an afforested site were added in reduced and oxidized redox state. Sulfate and acetate concentrations were analyzed, bacterial sulfate reduction (BSR) and CO₂ and CH₄ production quantified, and results analyzed by ANOVA. DOM was characterized by Fourier transformed infrared and fluorescence spectroscopy and analyzed for trace elements. CH₄ production (116 nmol cm⁻³ d⁻¹) and BSR rate (102 nmol cm⁻³ d⁻¹) were similar in ‘controls’. BSR in treatments ‘sulfate’ (73 nmol cm⁻³ d⁻¹) and ‘sulfide’ (118 nmol cm⁻³ d⁻¹) did not significantly differ from ‘controls’ but addition of DOM significantly diminished BSR down to 0.4 nmol cm⁻³ d⁻¹ (Kruskal Wallis test, p < 0.05). CH₄ production decreased with sulfate (16%, not significant) and sulfide addition (40%, p < 0.05) and CO₂ production increased (treatment ‘sulfate’, p < 0.05). Addition of all DOM extracts (67 mg L⁻¹) almost completely suppressed methanogenesis and CO₂ production (p < 0.05), but acetate accumulated compared to the control (p < 0.05). The DOM applied contained carboxylic, aromatic and phenolic moieties and metal contents typical for peat humic substances. We conclude that a toxic effect of the intensely humified DOM occurred on both methanogenic and sulfate reducing bacteria (SRB) but not on fermenting microorganisms. As yet it is not clear what might cause such a toxic effect of DOM on SRB and archaea.     

Lead in Three Peat Bog Profiles,Jura Mountains,Switzerland: Enrichment Factors,Isotopic Composition,and Chronology of Atmospheric Deposition

One metre cores were taken from three peat bogs in the Jura Mountains of Switzerland: Etang de la Gruère (EGr), La Tourbière des Genevez (TGe), and Praz Rodet (PRd). Dried peat samples were analyzed for lead (Pb) using the EMMA XRF and scandium (Sc) using INAA. Enrichment factors (EF) were calculated by normalizing to the background Pb/Sc ratio at EGr. Age dates were obtained using 210Pb (CRS Model) and confirmed using pollen chronostratigraphic markers in replicate cores. The isotopic composition of Pb in selected peat samples from EGr and TGe was determined using TIMS. Two pronounced peaks in Pb EF occur in the uppermost sections of all three bogs: the upper one corresponds to the late 1960's to late 1970's and the lower one to approximately 1900 to 1920. At EGr, sample 2f5 (11 cm, 86 µg/g Pb, EF = 91, and dated at A.D. 1967 ± 2) has an isotopic composition similar to that of leaded gasoline used in Berne in the 1970's. For comparison, the older peak at EGr (sample 2fl 1 at 29 cm, 84 µg/g Pb, EF = 79 and dated at A.D. 1905 ± 6) is significantly different. In contrast to these two samples, the isotopic composition of sample 2fl 5 (41 cm, 30 µg/g Pb, EF = 13 and pre-dating ca. A.D. 1800) approaches the present day "average terrestrial lead" and is likely to be predominately lithogenic. Therefore, the isotopic data show that the Pb introduced to the bog from leaded gasoline has not penetrated to this depth in the profile. A simple mass balance using the measured Pb concentrations and the isotopic compositions shows that vertical migration of gasoline Pb cannot explain the deeper, older peak in Pb EF. A more likely explanation is that the older peak reflects the rates of atmospheric Pb deposition during the first two decades of the 20th century. Taken together, the Pb concentrations, age dates, and isotopic data suggest that these peat profiles have preserved the record of changing rates of atmospheric Pb deposition. In addition, the results indicate that the isotopic composition of Pb deposited on the surface of the bogs gradually shifted away from lithogenic ratios as long ago as the middle of the 19th century, a change which clearly pre-dates the introduction of leaded gasoline.     

Geochemistry and geochemical differentiation on major elements in selected peat bog profiles (south-east of Poland)

Abstract

The geochemical differentiation of major elements in various peat bog profiles from Bieszczady Mountains Region (south-east of Poland) was compared to its botanical origin. Peat cores were taken from ombrotrophic, mesotrophic, and oligotrophic peatlands, which were developed in the stream valley of the River San. Twenty-four various peat samples were analysed for peat genus, degree of peat decomposition, ash content, total nitrogen, and total carbon content of hydrolytic matter as well as content of major elements: Na, K, Mg, Ca. The results show that the botanical composition of peat deposits is no reliable indication of their trophic status. The common feature of investigated Holocene peatlands is their valley localisation on the flood terrace. The specific character of local geommorpho8ogicml and hydrological condition caused that the bottom layer of all investigated bog profiles was made of wood peats (Piceaeti, Pineti, Alneti, and Saliceti peat). The geochemical investigations of stratigraphical profiles confirm that the presented peat bogs showed specific morphological separateness comparing to other raised bogs situated in mountains or lowlands     

Degradation of malathion, in aqueous extracts of asparagus (Asparagus officinalis)

Malathion was incubated in water extracts of vegetables at various temperatures and pH, and the amount of malathion present over time was analyzed by a gas chromatograph with a flame photometric detector. Malathion was degraded to a nondetectable level in a 1% asparagus extract incubated at pH 7.4 and 37 degrees C for 4 h. Carrot extract showed the second highest rate of malathion degradation (76%), followed by kale extract (23.7%), spinach extract (9.7%), and broccoli extract (1.5%) under the same conditions. The highest degradation rates of malathion were observed at 37 degrees C, when three different temperatures were tested (5, 25, and 37 degrees C) at pH 7.4. Rate constants were 0.134 min(-)(1) from a 1% asparagus solution and 0.095 min(-)(1) from a 0.5% asparagus solution. The highest degradation rate of malathion was achieved at pH 9 among the pHs tested (pH 4, 7.4, and 9) in a 0.5% asparagus solution. The 0.5% asparagus solution degraded dicarboxylic acid esters by almost 100% for dimethyl succinate and diethyl adipate, by 64% for diethyl acetyl succinate, and 30% for diethyl benzyl malonate when incubated at pH 9 for 20 min. The results support the hypothesis that the enzyme that degrades malathion in the asparagus solutions is a carboxylesterase.     

Different distribution of polycyclic aromatic hydrocarbons (PAHs) between Sphagnum and Ledum peat from an ombrotrophic bog in Northeast China

Journal of Soils and Sediments - The aims of this study are to investigate historical PAH deposition through the analysis of PAHs in bulk peat cores and reveal the different distribution of PAHs in...     

Dinitrogen (C2H2) fixation in relation to nitrogen fertilization of grey alder [Alnus incana (L.) Moench.] plantations in a peat bog

Summary Nitrogenase activity was measured in young grey alder plantations in a peat bog in central Sweden. The stands were treated in three ways: (1) daily irrigation during the growing season with a complete nutrient solution, including N; (2) application of bark ash or wood ash before planting; and (3) fertilization every second year with solid PK fertilizers. Acetylene reduction assays were performed on (1) detached nodules and attached nodules, either on (2) whole enclosed plants or (3) enclosed nodules. The acetylene reduction rate for the enclosed plants showed a maximum in July when mean values of nearly 80 mol C₂H₄ (g nodule dry matter)^-1 h^-1 were reached. No diurnal patterns were observed. The irrigated stands, with an N supply, showed overall nitrogenase activities that corresponded well with those of the other treatments. Only in the case of temporarily increased soil nutrient concentrations in the irrigated stands did the nitrogenase activity fall considerably. In 6-to 7-year-old intensively managed irrigated stands N₂-fixation was estimated as 85–115 kg N ha^-1 year^-1 which was about 55% of the total N uptake of the trees.     

Antioxidant and pro-oxidant activities of aqueous extracts and crude polyphenolic fractions of rooibos (Aspalathus linearis)

Unfermented rooibos tea is known to contain higher levels of total polyphenols and flavonoids than its fermented counterpart, making it the obvious choice for the preparation of flavonoid-enriched fractions. Evaluation of aqueous extracts and crude polyphenolic fractions of unfermented and fermented rooibos showed anti- and/or pro-oxidant activities, using a linoleic acid-Tween-buffer emulsion for lipid peroxidation and the deoxyribose degradation assay, based on a Fenton reaction model system containing FeCl3-EDTA and H2O2 for the generation of hydroxyl radicals. Except for the ethyl acetate fraction, with the highest total polyphenol (TP) content and offering the least protection presumably due to pro-oxidant activity, the inhibition of lipid peroxidation by the samples correlated moderately with their TP content in a linear relationship (r = 0.896, P < 0.01). Using the deoxyribose degradation assay, the pro-oxidant activity of the aqueous extracts and their crude polymeric fractions (0.1 mg/mL in the reaction mixture) was linear with respect to their dihydrochalcone (aspalathin and nothofagin) (r = 0.977, P = 0.023) and flavonoid (r = 0.971, P = 0.029) content. Pro-oxidant activity was demonstrated for pure aspalathin. Using the same assay, but with ascorbate added to regenerate Fe3+ to Fe2+, the aqueous extract and crude polymeric fraction of fermented rooibos displayed hydroxyl radical scavenging activity. Fermentation (i.e., oxidation) of rooibos decreased the pro-oxidant activity of aqueous extracts, which was contributed to a decrease in their dihydrochalcone content. The in vitro pro-oxidant activity displayed by flavonoid-enriched fractions of rooibos demonstrates that one must be aware of the potential adverse biological properties of potent antioxidant extracts utilized as dietary supplements.     

Chemical Characterization of Rain and Fog Water in the Cervenohorske Sedlo (Hruby Jesenik Mountains, Czech Republic)

Field study at the Cervenohorske sedlo (1,013 m a.s.l.) (Hruby Jesenik Mountains, the Czech Republic, Central Europe) during 1999–2002 has been conducted in order to analyse the chemistry of rain/snow water using bulk and throughfall collector and fog/cloud water using modified passive Grunow collector. Fog water input to coniferous forest (Picea abies) was quantified using canopy balance method. For all samples pH, and the concentrations of $ {\text{NH}}^{{\text{ + }}}_{{\text{4}}} $ , Ca²⁺, K⁺, Mg²⁺, Na⁺, Cl^?, $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ , and $ {\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} $ were measured. The volume-weighted mean pH value varied from 4.92 to 5.43 in open bulk precipitation, from 4.30 to 4.71 in throughfall and from 4.66 to 5.23 in fog water. The fog droplets generally contain higher ion concentrations than rainwater. The related enrichment factors lie between 1.1 and 10.7 for the relevant species. The fog samples exhibit higher concentrations of $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ and $ {\text{NH}}^{{\text{ + }}}_{{\text{4}}} $ as compared to the bulk samples during 2000–2002. $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ are 5.7–10.7 times more concentrated in fog water and $ {\text{NH}}^{{\text{ + }}}_{{\text{4}}} $ are 3.4–7.2 times more concentrated in fog water. These differences may result from the height and characteristics of formation of the droplets. Based on canopy balance method, the annual fog water inputs were estimated to be 22 and 19% of rain and snow annual amounts in 1999 and 2000, respectively. For $ {\text{NO}}^{{\text{ - }}}_{{\text{3}}} $ , $ {\text{NH}}^{{\text{ + }}}_{{\text{4}}} $ , and $ {\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}} $ , the contribution of fog deposition in total (bulk + fog) deposition is estimated as 54, 47, and 42%, respectively.     

Thermal properties of two organic (peat, pine bark) and two inorganic (perlite, clay) horticultural substrates

Thermal properties such as thermal conductivity and heat capacity of two organic (peat, pine bark) and two inorganic (perlite, expanded clay) horticultural substrates are studied. The thermal conductivity is determined using the apparatus described by JANSE & BOREL (1965). The relation between moisture content and moisture tension and thermal conductivity is determined for these horticultural substrates. The heat capacity is calculated as a function of the moisture content for the four horticultural substrates. A very good relation is found between thermal conductivity and soil moisture tension which can be used as a characteristic for the heat economy of horticultural substrates.     

Limited downward migration of pollutant metals (Cu,Zn, Ni,and Pb) in acidic virgin peat soils near a smelter

The distribution of pollutant heavy metals (Cu, Zn, Ni, Cd, and Pb) was determined in 11 acidic virgin peat profiles located along two transects moving away from a smelter plant in the Noranda region of Quebec. The levels of all five metals were found highest in the 0 to 15 cm layer at site near the smelter, and decreased progressively with the distance from the smelter, up to 42 km. Copper had the highest concentrations (5525 μg g^?1) followed by Pb and Zn. The maximum levels of total metals built up in the peat surface near the smelter were high, approximately reaching the threshold limits for phytotoxicity in peat soils. The amounts of heavy metals moving down and accumulating in the anaerobic zone of the peat profiles were limited. The distribution and enrichment ratios in the profiles showed that Cu, Zn, and Cd would have relatively higher mobility than Pb.     

Effect of aqueous and lipophilic mullet (Mugil cephalus) Bottarga extracts on the growth and lipid profile of intestinal Caco-2 cells

The importance of n-3 polyunsaturated fatty acid (n-3 PUFA) intake has long been recognized in human nutrition. Although health benefits, n-3 PUFA are subject to rapid and/or extensive oxidation during processing and storage, resulting in potential alteration in nutritional composition and quality of food. Bottarga, a salted and semi-dried mullet ( Mugil cephalus ) ovary product, is proposed as an important source of n-3 PUFA, having high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In this work, we investigated the extent of lipid oxidation of grated bottarga samples during 7 months of storage at -20 °C and room temperature under light exposure. Cell viability, lipid composition, and lipid peroxidation were measured in intestinal differentiated Caco-2 cell monolayers after 6-48 h of incubation with lipid and hydrophilic extracts obtained from bottarga samples at different storage conditions. The storage of bottarga did not affect the n-3 PUFA level, but differences were observed in hydroperoxide levels in samples from different storage conditions. All tested bottarga extracts did not show a toxic effect on cell viability of differentiated Caco-2 cells. Epithelial cells incubated with bottarga oil had significant changes in fatty acid composition but not in cholesterol levels with an accumulation of EPA, DHA, and 22:5. Cell hydroperoxides were higher in treated cells, in relation to the oxidative status of bottarga oil. Moreover, the bottarga lipid extract showed an in vitro inhibitory effect on the growth of a colon cancer cell line (undifferentiated Caco-2 cells).     

Isolation, characterization, and emulsifying properties of wattle seed (Acacia victoriae Bentham) extracts

Extracts from either ground whole wattle seeds or uncoated cotyledons were obtained using water, alkali, or ethanol. These extracts were then analyzed for their protein molecular weight and electrophoretic profiles using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and capillary electrophoresis, respectively. Water extracts and those from the cotyledons gave higher material yield and contained significantly more proteins than other extracts. Furthermore, the proteins ranged in molecular weight from 6 to 92 kDa, with the highest concentration between 27 and 61 kDa. Water extracts, even at very low protein concentrations (0.17-1.12%), formed stable emulsions, containing up to 50% canola oil, and these emulsions were affected by pH (4-9), ionic strength (0.25-1% NaCl), and retorting (115 degrees C for 30 min). The study showed that water-soluble wattle extracts have great potential as emulsifiers and stabilizers for the food industry, especially at low pH levels.     

Chemical,Physicochemical, and Nutritional Evaluation of Plantago (Plantago ovata Forsk)

Plantago ovata F. are small tan‐colored seeds with ≈30% weight husk. Plantago's husk high content of soluble fiber makes it a good lubricant of the intestinal track with demonstrated effects in lowering plasma cholesterol levels in humans and experimental animals. Plantago seeds grown in Northern Mexico were analyzed for proximate composition, combustion heat, soluble and insoluble dietary fiber, fatty acids, amino acids, and protein fractionation. In vitro digestibility and digestibility of dry matter, apparent and true digestibility, and net protein ratio (in vivo) were also analyzed. Plantago seeds had 17.4% protein, 6.7% fat, 24.6% total dietary fiber, 19.6% insoluble fiber, 5.0% soluble fiber, and a combustion heat of 4.75 kcal/g. Osborne fractionation (based on solubility) yielded albumin 35.8%, globulin 23.9%, and prolamin 11.7%. The oil from plantago seeds had a high percentage of linoleic acid (40.6%) and oleic acid (39.1%) and a minor proportion of linolenic acid (6.9%). In vitro protein digestibility of the plantago seed was 77.5%, suggesting a highly digestible protein. Lysine content was 6.82 g/100 g of protein, higher than wheat and oats (2.46 and 4.20 g/100 g of protein, respectively). Rat bioassays showed values of 89.6% digestibility of dry matter, 86.0% apparent digestibility, 88.1% true digestibility, and 4.40 net protein ratio corrected (NPRc). The importance of these findings is that plantago whole grain shows favorable nutritional quality when compared with cereals and legumes.     

Effect of species variation and processing on phenolic composition and in vitro antioxidant activity of aqueous extracts of Cyclopia spp. (Honeybush Tea)

The in vitro antioxidant activity of aqueous extracts prepared from four Cyclopia spp. (unfermented and fermented) was assessed using radical (ABTS *+) scavenging, ferric ion reduction, and inhibition of Fe2+-induced microsomal lipid peroxidation as criteria. Aqueous extracts of unfermented and fermented Aspalathus linearis (rooibos) and Camellia sinensis teas (green, oolong, and black) were included as reference samples. Qualitative and quantitative differences in phenolic composition were demonstrated for the Cyclopia spp. The xanthone glycoside, a.k.a. mangiferin, was the major monomeric polyphenol present in the Cyclopia extracts, with both unfermented and fermented C. genistoides extracts containing the highest quantities. Fermentation resulted in a significant reduction in extract yields and their total polyphenolic and individual polyphenol contents. Unfermented plant material should preferentially be used for preparation of extracts, as fermentation significantly ( P < 0.05) lowered antioxidant activity of all species, except in the case of C. genistoides, where the ability to inhibit lipid peroxidation was not affected. Unfermented plant material also retained the highest concentration of mangiferin. Overall, extracts of unfermented Cyclopia were either of similar or lower antioxidant activity as compared to the other teas. However, the presence of high levels of mangiferin merits the use of Cyclopia spp. and, in particular, C. genistoides, as an alternative herbal tea and potential dietary supplement.     

Isotope (C and C) analysis of deep peat CO2 using a passive sampling technique

We developed and tested a new method to collect CO₂ from the surface to deep layers of a peatland for radiocarbon analysis. The method comprises two components: i) a probe equipped with a hydrophobic filter that allows entry of peat gases by diffusion, whilst simultaneously excluding water, and, ii) a cartridge containing zeolite molecular sieve that traps CO₂ passively. We field tested the method by sampling at depths of between 0.25 and 4 m at duplicate sites within a temperate raised peat bog. CO₂ was trapped at a depth-dependent rate of between ∼0.2 and 0.8 ml d⁻¹, enabling sufficient CO₂ for routine ¹⁴C analysis to be collected when left in place for several weeks. The age of peatland CO₂ increased with depth from modern to ∼170 BP for samples collected from 0.25 m, to ∼4000 BP at 4 m. The CO₂ was younger, but followed a similar trend to the age profile of bulk peat previously reported for the site (Langdon and Barber, 2005). δ¹³C values of recovered CO₂ increased with depth. CO₂ collected from the deepest sampling probes was considerably ¹³C-enriched (up to ∼+9‰) and agreed well with results reported for other peatlands where this phenomenon has been attributed to fermentation processes. CO₂ collected from plant-free static chambers at the surface of the mire was slightly ¹⁴C-enriched compared to the contemporary atmosphere, suggesting that surface CO₂ emissions were predominantly derived from carbon fixed during the post-bomb era. However, consistent trends of enriched ¹³C and depleted ¹⁴C in chamber CO₂ between autumn and winter samples were most likely explained by an increased contribution of deep peat CO₂ to the surface efflux in winter. The passive sampling technique is readily portable, easy to install and operate, causes minimal site disturbance, and can be reliably used to collect peatland CO₂ from a wide range of depths.     

Chemical composition, iron bioavailability, and antioxidant activity of Kappaphycus alvarezzi (Doty)

Kappaphycus alvarezzi, an edible seaweed from the west coast of India, was analyzed for its chemical composition. It was found that K. alvarezzi is rich in protein (16.24% w/w) and contains a high amount of fiber (29.40% w/w) and carbohydrates (27.4% w/w). K. alvarezzi showed vitamin A activity of 865 mug retinal equivalents/100 g of sample. It contained a higher quantity of unsaturated fatty acids (44.50% of the total), in which relative percentage of oleic acid was 11%, cis-heptadecanoic acid 13.50%, and linoleic acid 2.3% and 37.0% of saturated fatty acids (mainly heptadecanoic acid). K. alvarezziwas also found to be good source of minerals, viz 0.16% of calcium, 0.033% of iron, and 0.016% of zinc, which are essential for various vital biological activities. Bioavailability of iron by in vitro methods showed a higher efficiency in intestinal conditions than in stomach conditions. Ascorbic acid influenced higher bioavailability of iron. Successive extracts of n-hexane, acetone, ethyl acetate, ethanol, and direct extractables of chloroform/methanol (1:1 and 2:1) were screened for antioxidant activity using a beta-carotene linoleic acid model system (B-CLAMS), DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) model system and hydroxyl radical scavenging activity. The chloroform/methanol (2:1) extract has shown 82.5% scavenging activity at 1000 ppm. Acetone fraction extracts at the 1000 ppm level showed 63.31% antioxidant activity in beta-carotene linoleic acid system. The acetone extract showed 46.04% scavenging activity at 1000 ppm concentration. In the case of hydroxyl radical scavenging activity, all the extracts showed better activity at the concentrations of 25 and 50 ppm, where at the 50 ppm level ethyl acetate extract showed 76.0%, acetone 75.12%, and hexane 71.15% activity, respectively. Results of this study suggest the utility of K. alvarezzi (Eucheuma) for various nutritional products, including antioxidant for use as health food or nutraceutical supplement.     

Measured and modelled retention of inorganic sulfur in soils and subsoils (Harz Mountains,Germany)

Atmospheric deposition has resulted in an accumulation of inorganic sulfur (S) in many forest soils. At Sösemulde (Harz Mountains) samples from 5–240 cm depth were analysed. Most sulfate (SO₄) is accumulated at about 30–60 cm depth: 8.5–9.5 mmol_c kg^–1. Large amounts can also be retained in > 100 cm. To assess changes in SO₄ dynamics in time,adsorption isotherms have been included in several process-oriented models, e.g., in MAGIC. The Lange Bramke (LB) Model is the first model used on the catchment scale containing solubility products for the hydroxosulfate minerals jurbanite and alunite. By reconstructing the long-term acidification history (140 years) both models were successfully calibrated to a 14-year deposition, soil and streamwater data set at Lange Bramke catchment (Harz Mountains). According to MAGIC the present accumulation of SO₄ in 0 –80 cm is 8.7 mmol_c kg^–1, while according to the LB-Model 10.2 mmol_c kg^–1 are stored as jurbanite. Both models predicted 4.5 mmol_c kg^–1 SO₄ in the subsoil layer, retained as alunite in the LB Model. These values correspond to the amounts measured in soil and subsoil samples at Sösemulde, respectively. However, for future scenarios with decreasing S inputs the models show different developments in SO₄ concentrations. Changes in MAGIC are gradual whereas the LB model predicts stepwise decreasing SO₄ values as soon as previously stored hydroxosulfates are fully dissolved. Such concentration jumps have not been observed.     

Antioxidant,prooxidant, and cytotoxic activities of solvent-fractionated dandelion (Taraxacum officinale) flower extracts in vitro

This study was conducted to investigate the chemical antioxidant and bioactive properties of the water (WF) and ethyl acetate fractions (EAF) derived from dandelion (Taraxacum officinale) flower extract (DFE). HPLC analysis showed the presence of both luteolin and luteolin 7-glucoside in the DFE, which contributed to noted in vitro antioxidant and Caco-2 cell cytotoxic activities. Both WF and EAF of DFE exhibited free radical scavenging activities in a stable 2,2-diphenyl-1-picrylhydrazyl radical model and reduced the breakage of supercoiled DNA strand induced by both non-site-specific and site-specific hydroxyl radical. Oxidation of structured phosphatidylcholine liposome induced by peroxyl radical was reduced in the presence of both EAF and WF. EAF had greater (p < 0.05) affinity to scavenge peroxyl radical than WF, as measured by the formation of conjugated diene. At low concentration, prooxidant activity of both fractions was observed in Cu(2+)-induced structured liposome and hLDL oxidation models, thus indicating that the reducing power of the DFE had resulted in generation of reactive cuprous ion. However, at high concentrations the EAF did not promote oxidation in the presence of Cu(2+), suggesting that the free radical scavenging activity of this fraction was sufficient to minimize the potential oxidative mechanism attributed to the metal ion reducing activity associated with prooxidant activity.     

Chemical characterization of red wine grape (Vitis vinifera and Vitis interspecific hybrids) and pomace phenolic extracts and their biological activity against Streptococcus mutans

Grapes are rich sources of potentially bioactive polyphenols. However, the phenolic content is variable depending on grape variety, and may be modified during vinification. In this study, we examined the chemical composition and biological activity of phenolic extracts prepared from several red wine grape varieties and their fermented byproduct of winemaking (pomace) on some of the virulence properties of Streptococcus mutans a well-known dental pathogen. Grape phenolic extracts were obtained from Vitis vinifera varieties Cabernet Franc and Pinot Noir and Vitis interspecific hybrid varieties Baco Noir and Noiret. The anthocyanins and flavan-3-ols content were highly variable depending on grape variety and type of extract (whole fruit vs fermented pomace). Nevertheless, all grape phenolic extracts remarkably inhibited glucosyltransferases B and C (70-85% inhibition) at concentrations as low as 62.5 microg/mL (P < 0.01). Furthermore, the glycolytic pH-drop by S. mutans cells was inhibited by the grape extracts without affecting the bacterial viability; an effect that can be attributed to partial inhibition of F-ATPase activity (30-65% inhibition at 125 microg/mL; P < 0.01). The biological activity of fermented pomace was either as effective as or significantly better than whole fruit grape extracts. The results showed that grape phenolic extracts, especially from pomace, are highly effective against specific virulence traits of S. mutans despite major differences in their phenolic content.